openkylin
/
platform_kernel-5.15
mirror of https://gitee.com/openkylin/platform_kernel-5.15.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

ANDROID: softirq: defer softirq processing to ksoftirqd if CPU is busy with RT 

Defer the softirq processing to ksoftirqd if a RT task is running
or queued on the current CPU. This complements the RT task placement
algorithm which tries to find a CPU that is not currently busy with
softirqs.

Currently NET_TX, NET_RX, BLOCK and TASKLET softirqs are only deferred
as they can potentially run for long time.

Bug: 168521633
Change-Id: Id7665244af6bbd5a96d9e591cf26154e9eaa860c
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
[satyap@codeaurora.org: trivial merge conflict resolution.]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
[elavila: Port to mainline, squash with bugfix]
Signed-off-by: J. Avila <elavila@google.com>
This commit is contained in:
Pavankumar Kondeti 2017-06-28 12:00:31 +05:30 committed by J. Avila
parent 8d19443b0b
commit 0578248bed
3 changed files with 42 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/sched.h
View File

@ -1634,6 +1634,16 @@ current_restore_flags(unsigned long orig_flags, unsigned long flags)
extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
#ifdef CONFIG_RT_SOFTINT_OPTIMIZATION
extern bool cpupri_check_rt(void);
#else
static inline bool cpupri_check_rt(void)
{
return false;
}
#endif
#ifdef CONFIG_SMP
extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);

13
kernel/sched/cpupri.c
View File

@ -331,3 +331,16 @@ void cpupri_cleanup(struct cpupri *cp)
for (i = 0; i < CPUPRI_NR_PRIORITIES; i++)
free_cpumask_var(cp->pri_to_cpu[i].mask);
}
#ifdef CONFIG_RT_SOFTINT_OPTIMIZATION
/*
* cpupri_check_rt - check if CPU has a RT task
* should be called from rcu-sched read section.
*/
bool cpupri_check_rt(void)
{
int cpu = raw_smp_processor_id();
return cpu_rq(cpu)->rd->cpupri.cpu_to_pri[cpu] > CPUPRI_NORMAL;
}
#endif

23
kernel/softirq.c
View File

@ -259,6 +259,16 @@ static inline bool lockdep_softirq_start(void) { return false; }
static inline void lockdep_softirq_end(bool in_hardirq) { }
#endif
#define softirq_deferred_for_rt(pending) \
({ \
__u32 deferred = 0; \
if (cpupri_check_rt()) { \
deferred = pending & LONG_SOFTIRQ_MASK; \
pending &= ~LONG_SOFTIRQ_MASK; \
} \
deferred; \
})
asmlinkage __visible void __softirq_entry __do_softirq(void)
{
unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
@ -266,6 +276,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
int max_restart = MAX_SOFTIRQ_RESTART;
struct softirq_action *h;
bool in_hardirq;
__u32 deferred;
__u32 pending;
int softirq_bit;
@ -277,14 +288,14 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
current->flags &= ~PF_MEMALLOC;
pending = local_softirq_pending();
deferred = softirq_deferred_for_rt(pending);
account_irq_enter_time(current);
__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
in_hardirq = lockdep_softirq_start();
restart:
/* Reset the pending bitmask before enabling irqs */
set_softirq_pending(0);
set_softirq_pending(deferred);
__this_cpu_write(active_softirqs, pending);
local_irq_enable();
@ -321,14 +332,18 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
local_irq_disable();
pending = local_softirq_pending();
deferred = softirq_deferred_for_rt(pending);
if (pending) {
if (time_before(jiffies, end) && !need_resched() &&
--max_restart)
goto restart;
wakeup_softirqd();
}
#ifdef CONFIG_RT_SOFTINT_OPTIMIZATION
if (pending | deferred)
wakeup_softirqd();
#endif
lockdep_softirq_end(in_hardirq);
account_irq_exit_time(current);
__local_bh_enable(SOFTIRQ_OFFSET);